Jirka A, et al. - In this study involving patients with short bowel syndrome (SBS), researchers determined whether citrulline impacts whole body protein metabolism. Long after surgery, nine adults with non-malignant SBS who were in near-normal nutritional status without any artificial nutrition were enlisted in this pilot, randomized, double-blind, cross-over study. In SBS patients, oral citrulline supplementation enhances citrulline and arginine bioavailability. Findings revealed that oral citrulline supplementation has no anabolic effect on the metabolism of whole body protein in patients with SBS in good nutritional status, in the late phase of intestinal adaptation, and with near-normal baseline citrulline homeostasis. Whether oral citrulline affects the anabolism of whole body protein in severely malnourished SBS patients during the early adaptive period and with baseline plasma citrulline below 20 μmol/L needs further investigation.